I think Star Wars would be screwed most ways.
The Imperium would just grind them down beneath their immense weight.
The Orks would... well, good luck exterminating them. They'll probably just plague the SW universe for Eons to come before winning in the end as they are the last one standing.
Tyranids... oh well, if enough hive fleets put their eyes on the Star Wars universe, it will fall, no matter what!